The production of organic compounds using synthesis gas, which is a mixture of carbon monoxide and hydrogen, or from carbon monoxide as one of the reactants has been known for a significant period of time. It is well known that one can produce methanol directly from synthesis gas and that methanol can be further reacted by hydroformylation, homologation and carbonylation reactions to produce acetaldehyde, ethanol and acetic acid or its methyl ester, respectively. It is also known that alcohols, esters, ethers, and other organic compounds can be reacted with synthesis gas or carbon monoxide to produce oxygenated organic compounds. The difficulties, however, have resided in the ability to carry out any one of these chosen reactions to produce the desired compound at acceptable efficiency, conversion rate and selectivity.
In almost all instances the reaction is generally catalyzed using a Group VIII transition metal compound as catalyst and a halogen as the promoter. It is known that many other metal compounds and promoters can be used. In addition, the prior art has disclosed the use of secondary activators or ligands in conjunction with the metal catalysts and promoters. These secondary activators can be other metallic salts or compounds, amines, phosphorus compounds, as well as a multitude of other compounds that have been disclosed in the published literature. Thus, a typical catalyst system contains the metal atom catalyst, promoter and, optionally, ligands, solvents and secondary activators. Though a significant amount of literature does exist describing the production of acetic acid, to our knowledge it does not disclose or suggest our invention. Several of the pertinent patents in this area are discussed below.
U.S. Pat. No. 4,133,966, filed by Wayne R. Pretzer et al and issued Jan. 9, 1979, discloses the process for the homologation of methanol to ethanol using a catalyst system containing cobalt acetylacetonate, a trivalent phosphorus or trivalent arsenic or trivalent antimony organic ligand, an iodine compound and a ruthenium compound. This is not the system employed in the instant invention.
U.S. Pat. No. 4,111,837, filed by Paul D. Taylor and issued on Sept. 5, 1978, relates to the use of a heterogeneous co-catalyst system for the homologation of alkanols. The co-catalyst system contains cobalt and rhenium metal. The catalyst disclosed is not the catalyst of the instant invention and, further, there is no mention of the use of an alkali metal atom.
In U.S. Pat. No. 4,233,466 and U.S. Pat. No. 4,253,987, filed by Rocco A. Fiato and issued on Nov. 11, 1980 and Mar. 3, 1981, respectively, there are disclosed processes and catalysts for the production of ethanol by the homologation reaction of methanol and synthesis gas using a system containing cobalt atom, ruthenium atom, iodine atom and a phosphine ligand. There is no disclosure or suggestion in these references of the advantages to be realized by the addition of an alkali metal atom.
U.S. Pat. No. 4,239,924 and U.S. Pat. No. 4,239,925, filed by Wayne R. Pretzer et al and issued on Dec. 16, 1980, disclose a process for selectively producing ethanol using a system containing a specifically defined cobalt tricarbonyl complex, an iodine compound, and a ruthenium compound in the methanol homologation reaction. The basic distinction between the two patents is the use of aliphatic substituted complexes in U.S. Pat. No. 4,239,924 and aromatic substituted complexes in U.S. Pat. No. 4,239,925. Neither patent makes any mention or suggestion on the use of an alkali metal atom in the process.
U.S. Pat. No. 4,324,927, filed by Jean Gauthier-Lafaye et al and issued on Apr. 13, 1982, describes a process for the homologation of methanol to produce ethanol using a system containing cobalt atom, ruthenium atom and both an alkyl halide and an ionic halide.
U.S. Pat. No. 4,304,946, filed by Nobuo Isogai and issued on Dec. 8, 1981, describes the homologation of methanol to produce ethanol using a cobalt sulfide compound or a mixture of a cobalt sulfide compound and a nitrogen-containing and/or a phosphorus containing compound. The system is free of iodine atom.
U.S. Pat. No. 306,091, filed by Jean Gauthier-Lafaye and issued on Dec. 15, 1981, describes the carbonylation of methanol to produce acetaldehyde using a system containing cobalt atom, ruthenium atom, ionic halide and an alkyl halide wherein the cobalt concentration is at most 50 mgm atoms per liter of reaction. The emphasis in this patent is the production of acetaldehyde and only trace amounts of by-product ethanol are shown to be produced. On the other hand, in this instant application ethanol is the desired product.
U.S. Pat. No. 4,328,379, filed by F. J. Devon and issued on May 4, 1982, describes the homologation of methanol to produce ethanol using a cobalt-iodine catalyst system in the presence of a perfluorocarboxylate anion. There is no disclosure of the presence of ruthenium and alkali metal atom in the catalyst system.
U.K. Patent Application GB 2,083,465A, filed by N. Isogai et al and published on Mar. 24, 1982, for the homologation of methanol to produce ethanol using a heterogeneous catalyst system comprising cobalt phosphate as the main catalyst. The applicants also disclose the use of a Group VIII metal as co-catalyst. They do not mention any use of an alkali metal atom in the catalyst system.